Recent infrared (IR) video camera systems employing IR sensitive elements, e.g., a cooled or uncooled Charged Coupled Device (CCD) focal plane array, pyroelectric detector or the like, have been employed in infrared thermography systems for performing thermographic inspections or surveys of large numbers of elements. Thermographic images of an element may then be compared with a control image or other previously recorded thermographic image of the same scene or element. Such systems may be employed, e.g., in industrial facilities for plant maintenance, or the like, in which failures of electromechanical equipment, process equipment or other devices may be predicted based on abnormalities or “thermal events” detected in a live or recorded thermal image of the device being surveyed. Such thermographic surveys may also be employed in agricultural, medical, veterinary medical, law enforcement and military applications. In such applications, a thermographer may prepare a thermographic survey comprising a list of devices, objects or infrared scenes, called elements, to be recorded or surveyed. Each element is then periodically recorded using a thermographic video camera to record thermal video images of the elements of the survey. Thereafter, each video image of an element of the survey may be reviewed for comparison with a previously recorded control image of the element. By comparing the survey image with the control image, a thermal abnormality or thermal event may be detected. Such a thermal event may indicate a pending failure of the element. One such thermographic inspection system is disclosed by Piety et al. in U.S. Pat. No. 5,386,117.
Piety et al. disclose a mobile thermography system comprising an infrared camera, an ordinary visible image video camera, a personal computer, (PC), including an internal digital memory and a disk drive for digital data storage, a video recorder for recording analog video data, an LCD touch screen display device, a pen digitizer, various power storage devices, a system controller for operating various software which may be used to control and communicate between the various system elements, as well as, various other measuring devices, all mounted onto a mobile unit for ease of movement through a facility to be surveyed. Piety et al. also disclose a fixed base station computer including a digital data processor, for operating various digital data processing programs and including a video display and a printer for viewing video images, a memory, a disk drive, for digital data storage, an analog video recorder and analog video image processing equipment. In this case the mobile unit may be connected via communication ports with the base station computer at the beginning and end of each survey so that digital and or analog images, as well as, image identifying data may be communicated from the base unit to the mobile unit or from the mobile unit to the base unit as required.
According to Piety et al. software running on the base station computer is used to set up a framework of the thermographic survey. Such information as an element identifying name or control image, the type of element being surveyed, how to survey the element, fault types to look for, templates, notes, forms and the like are uploaded from the base station computer to the mobile unit prior to starting a survey to prompt the thermographic surveyor through the survey element by element and to record all information needed to generate a final report in the event a fault is discovered. After data collection is completed, the mobile unit is again connected to the base station computer and the collected survey images as well as other data which may have been entered by an operator during the survey are downloaded from the mobile unit to the base station computer for analysis and report generation.
One problem with this approach is that the thermographic surveyor is prompted through the thermographic survey in the predetermined order according to a survey route which is established by the original thermographic survey framework set up at the base station computer. In cases where the surveyor may wish to change the order or the route of the survey, the prompt information must be scrolled through in order to find the identifying information associated with a desired survey element. Since the survey may include many hundreds of images, this presents a problem to the surveyor when the order of the survey is changed. Another problem with the prior art approach is that many of the survey elements may be nearly identical, e.g. an electrical switch panel may contain tens or hundreds of substantially identical switches to be surveyed. In this case, an operator may confuse one switch with another. Even the element identifying information stored by the mobile unit may be confusing since element names and element control images may be very similar. For these reasons, an operator could easily loose the sequence of the survey thereby falsely identifying subsequent recordings.
A further disadvantage associated with the prior art is that occasionally a re-survey may be required to confirm or reevaluate a thermal event for one or a portion of the elements of the survey. By the prior art methods, a surveyor would be forced to scroll through the entire survey to reach the data associated with the element or elements to be resurveyed.